Fiber optic network with wavelength-division-multiplexed transmission to customer premises

ABSTRACT

A fiber optic network comprises an optical fiber connection (one fiber or two) from a central office to an intelligent interface device in the subscriber&#39;s premises. The central office includes a serving node transceiver providing communication links to/from at least a narrowband switch and a broadband switch for providing narrowband and broadband service routing. The network includes at least one passive power splitter/combiner for passing all wavelengths on the optical fiber connection between the serving node transceiver and the intelligent interface devices. All wavelengths are provided to each customer and bandwidth on the optical fiber loop is dynamically allocated for individual services on demand through two-way wavelength division multiplexing and demultiplexing as well as any necessary signal format conversions. The network has media access control functionality and utilizes a dynamic media access control procedure for allocation of the bandwidth.

FIELD OF THE INVENTION

This invention relates generally to the distribution of information andcommunications services via an optical fiber network. In particular, theinvention relates to the control of wavelength division multiplexing inoptical fiber connections of a network in order to more efficiently andcost-effectively distribute information.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is related to U.S. application Ser. No. 08/656,879,filed May 30, 1996.

BACKGROUND OF THE INVENTION

The distribution of high bandwidth information, such as video, isfrequently carried out over so-called hybrid fiber/coaxial (HFC)systems. These systems generally distribute the high bandwidthinformation in one direction only. The fiber optics are connected to thehead end of the system at the information source and transport a largenumber of individual signals or channels over the majority of thedistance between the head end and the user locations. The fiber opticsusually terminate at a point relatively close to a user location orgroup of user locations and are transported over coaxial cables from thetermination point to the user location or group of user locations.

A typical video signal distribution system for distributing TV programsfrom a central location is depicted in U.S. Pat. No. 4,994,909 to Graveset al. In that system, the television signals are transmitted by fiberoptic connections to an interface network 30 and are transmitted bycoaxial cables from there to a number of television receivers.

Many of the HFC systems are referred to as fiber to the curb systems.See, for example, U.S. Pat. No. 5,262,883 to Pidgeon and U.S. Pat. No.5,133,079 to Ballantyne et al. Such systems typically use an optical toelectrical converting terminal at the curb, sometimes referred to as anoptical network unit (ONU), and deliver voice and video downstream tothe home from the terminal using coaxial cable or twisted copper pairtechnology. U.S. Pat. Nos. 5,181,106, 5,189,673 and 5,303,229, commonlyassigned to Alcatel Systems, discuss a network having atelecommunications central office connected to remote terminals by fiberoptics with the connections to the customers over twisted pair(narrowband) and coaxial cable (broadband). POTS decoding and D/Aconversion take place at the ONU and the digital signals limited tovideo information are decoded and D/A converted at the set top in theCPE.

The installation of ONUs and other active electronic units outside thepremises (on telephone poles, electric curbside units, etc.) in fiber tothe curb systems is labor and cost intensive and exposes them toinclement weather. The installation of electronic units outside thepremises to provide conversion to wire transport also erases theadvantage of additional security provided by the extreme difficulty intapping fiber optics. Even those fiber optic systems having fiber opticdrops from the curb to the home, such as in U.S. Pat. No. 5,325,223 toBears, convert the optical signals to electrical signals at the curbunits for the purpose of multiplexing and demultiplexing.

Typical fiber to the curb systems also are not efficient from thenetwork side or the customer side in their use of bandwidth over thefiber, thus ultimately increasing the cost of the system. From thenetwork perspective, the systems do not use bandwidth in an effectiveway. They also tend to be very rigid and to follow standard NorthAmerican digital hierarchies or vendor proprietary hierarchies. Suchinterfaces also tend to be very channelized and to switch large chunksof bandwidth in a discrete type manner regardless of the customer'sactual bandwidth needs. The upstream transmission is usually restrictedto signalling messages, and the upstream transmission rate back into thenetwork from the customer is extremely bandwidth limited and is nottruly dynamic.

Any switching of signals or bandwidth typically occurs at the headendwith a point to point transmission system from the headend to the ONUlocated close to the end user. The optical fiber or fiber optic pair tothe ONU carries a very high bandwidth rate which is then subdivided intosmaller bandwidths for each one of a plurality of customer premises. Forexample, the full bandwidth on the fiber may be OC-12, and thatbandwidth may be subdivided into 8 different segments, each segmenttransporting information for one premises over coaxial cable or twistedcopper pairs to that premises. See for example, copending, commonlyassigned, patent application Ser. No. 08/413,215 filed on Mar. 28, 1995entitled "Full Service Network with Distributed Architecture".

For video and POTS, all of the switching usually occurs at the headendwith channelized transmission and access back through the activeelectronics at the ONU or elsewhere in the network. For example, in U.S.Pat. No. 5,136,411 to Paik et al, electrical service request signalsfrom subscribers are converted into optical service request signals andsent to a headend terminal. The headend terminal then selects among anumber of channels for transmission to the subscribers. In U.S. Pat. No.4,506,387 to Walter and U.S. Pat. No. 4,709,418 to Fox et al, users cansend an upstream request for a selected video program to be delivereddownstream at a high rate over fiber optics to a receiving unit at theuser's location where the video signals are then displayed. Whilechannels or video programs can be selected, there is nevertheless nodynamic relationship in the allocation of fiber optic bandwidth betweenthe headend and the customer.

From the customer side, the restricted upstream transmission preventscustomers connected to fiber to the curb systems from being able togenerate signals on the network for two-way transmission in a manneranalogous to home page providers on the Internet. It would be preferableto have a system which enables a customer to send as well as receive,for example, full motion video to and from another location and whichfacilitates transmission of the content and routing signals.

Distribution systems which utilize optical fibers for the entiretransmission path to the home are known but are generally regarded asbeing substantially more expensive and less flexible than HFC or fiberto the curb systems.

U.S. Pat. No. 4,891,694 to Way pertains to a fiber optic cabletelevision distribution system in which each customer location isconnected to a remote terminal via a dedicated optical fiber. Televisionsignals are transmitted by optical fiber to a remote terminal and intoCATV tuners. An optical fiber connects the remote terminal to thecustomer location, however the remote terminal is not the interface tothe home.

U.S. Pat. No. 5,272,556 to Faulkner et al pertains to distributing HDTVsignals from a transmitter at a head station to a number of receiverslocated at customer stations along an optical network.

U.S. Pat. No. 4,135,302 to Cutler pertains to a broadcasting system inwhich a signal path between a central station and a plurality ofsubscribers includes fiber optic transmission lines. The optical fibersextend over the whole length of the transmission paths between anelectro-optical transducer at the central station and a distributionpoint or photo-sensitive detector of each of the plurality ofsubscribers.

Although these optical fiber systems are capable of delivering a largeamount of information, they nevertheless offer little flexibility inswitching between multiple channels or services.

Some fiber optic systems utilizing wavelength division multiplexing andproviding telephone, data and video services are known in the prior art.For example, U.S. Pat. Nos. 5,121,244 and 5,175,639 to Takasaki suggesta fiber optic system having auxiliary fiber optic transmission lines foruse when upgrading to higher bandwidth services. Although the fiberoptic lines may be wavelength division multiplexed, the multiplexers anddemultiplexers at both ends merely switch the entire bandwidth output ofeach fiber optic line. There is no provision made for altering orallocating different customer bandwidths over a single fiber optic line.Takasaki, for example, suggests providing auxiliary transmission linesfor flexibility in providing high bandwidth services.

U.S. Pat. No. 5,221,983 to Wagner also discusses a fiber to the homesystem utilizing wavelength division multiplexing. A central office isconnected to a plurality of remote nodes by a fiber. Each node connectsto a subscriber premises via another fiber. The central office containswave-division multiplexing modules, and their output is connected byfibers to the remote node.

U.S. Pat. No. 4,763,317 to Lehman et al discusses a communicationnetwork structured to carry both wideband and narrowband communicationsvia optical fibers to the home. Examples of the various services thatthe network provides include telephony, audio, telemetry,packet-switched interactive data, facsimile, one-way video (TV),restricted one-way video (video-on-demand) and video conferencing.Network interface equipment at the subscribers' premises connects toremote network nodes via distribution optical fibers. Each distributionoptical fiber is wavelength-division multiplexed and carries modulated(pulse-analog, pulse-code, or differential pulse-code) wideband digitalchannels as well as a multiplexed channel comprising 32time-division-multiplexed narrowband digital channels. One of thenarrowband channels carries all signaling messages.

Each remote node in the Lehman et al system comprises a digitalspace-division switch for wideband channels, and a digital time-divisionswitch for narrowband channels. All switches are controlled by a centralnode control complex over a control bus and its extensions. Signalingmessages are transferred between the signaling-message-carryingnarrowband channels and the central node complex by a subscribersignaling subsystem, via the narrowband switch and the control bus. Thecentral node optionally includes interfaces to other communicationsystems, as well as trunk communication fiber and Common Channel Interoffice Signaling (CCIS) fiber connections to other central nodes of thenetwork. The central node in FIG. 2 has fibers that transmit to theremote nodes, and the remote nodes have fiber connections to varioussubscribers.

Lehman et al is limited in flexibility because it utilizes a predefinedstatic channelization on the loop fiber. If the service or bandwidthrequirements of a subscriber change quickly, there is no means forestablishing various connections through allocated bandwidth on thefiber(s) between the home and the central office. In particular, thereis no means provided which make it possible to dynamically allocatebandwidth on the fiber distribution loops on demand.

Completely fiber optic systems such as the one in Lehman et al havelimited or no built-in functionality for dynamic access control by thesubscriber. Thus, there is no functionality that would allow asubscriber served by a fiber optic system to, for example, request,receive and pay for only the bandwidth which he desires.

Furthermore, completely fiber optic systems are usually limited to aspecific service context such as either a fiber video system or a fiberPOTS system. There is a need for an interface which canmultiplex/demultiplex as required whatever fiber optic signal is sent,thus enabling more transparent access to different information sourceswith different bandwidth requirements.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide methods andapparatus which will overcome the problems and disadvantages of knownfiber optic networks and will meet the needs discussed above.

It is an object of the present invention to deliver many differentservices to the customer using a single fiber optic network.

It is also an object of the invention to use fiber transport from acentral office to an interface type device located within the customerpremises.

It is a further object of the present invention to deliver servicesignals over a fiber transport, using various network identifiers thattake the service signals through encoding technology such as ATM, tointelligent network interfaces at the customer premises which opticallyreceive those service signals and deliver them to electrical devices inthe customer premises.

It is also an object of the present invention to provide a fiber opticsystem having a dynamic bandwidth interface with the fiber at the pointof end use having true dynamic bandwidth for whatever service issubscribed to or for whatever customer access is required.

It is a further object of the present invention to provide anintelligent interface inside the customer premises and to providemulti-service distribution inside the customer premises, includingdynamic distribution between or within services.

A further object is to provide a long-term costeffective solution bydelivering all wavelengths of a wavelength-division-multiplexed fiberoptic network to all customers and using electronics at the customers'premises to discriminate the wavelengths in order to manage thebandwidth of the network.

A preferred embodiment of the invention provides an optical fiberconnection (one fiber or two) of a common plurality of wavelengths froma serving node transceiver in a central office to each one of aplurality of intelligent interface devices in the customers' premises.The central office includes at least a narrowband switch and a broadbandswitch. The narrowband switch provides voice grade telephone servicerouting. The broadband switch provides routing for video services andmay comprise an Asynchronous Transfer Mode (ATM) switch, an opticalswitch or the like. Preferably, the central office also includes apacket data switch.

At the subscriber premises, the intelligent interface device providesthe connection to the optical fiber and performs two-way multiplexingand demultiplexing as well as any necessary signal format conversions.The intelligent interface device may also provide similar two-wayoptical to electrical conversion and interfacing for ISDN, telemetry,packet data, etc. Traditional media (twisted pair, coaxial cable, etc.)may be used inside the customer premises for the delivery of the variousservices.

The intelligent interface device in the subscriber premises alsoprovides a broadband connection. The broadband link within the customerpremises may take the form of an optical network, or the on-premisesbroadband distribution may rely on wireless transmissions.Alternatively, the interface may include equal division splitters toprovide separate links serving individual terminal devices.

The intelligent interface device is thus analogous to an electricaldistribution panel, in that the interface device distributesdemultiplexed signals throughout the house. If multiple RF signals aredelivered, they are converted and modulated at the interface. In thisregard, the interface device basically performs the functionalityanalogous to an optical network unit (ONU) and/or a network interfacemodule (NIM) in a terminal, except now at a central point in the home.

The network has media access control functionality and utilizes adynamic media access control procedure. Bandwidth on the optical fiberloop is dynamically allocated to individual services on demand. Theoptical fiber(s) can carry three different wavelengths, and allocationof bandwidth can include wavelength selection as well as bit rateallocation.

A media access control unit in the interface controls communication overthe fiber loop and allows total control of the optical fiber bandwidthallocation to each service. The customer may carry out any desired ornecessary communications processing at the interface rather than at asettop box for a TV or VCR. For example, at the interface, conversionfunctions could be made to, for example, get picture in picture, watchand tape television programs at the same time, watch television andreceive data, etc.

The central office includes a similar interface device connected to thesubscriber's optical loop. The interface device in the central officeprovides two-way conversion between optical and electrical signals andperforms the multiplexing and demultiplexing of the signals carried onthe loop. The central office interface couples the various signals onthe loop to and from the voice grade narrowband switch, the broadbandswitch and the packet data switch, as needed.

The intelligent interface device preferably receives power from the ACpower grid in the subscriber's premises. Alteratively, the interfacedevice may receive power from the central office via a twisted wirepair, e.g. the old telephone loop replaced by the installation of theoptical fiber loop. The interface may also control any alarming, powermonitoring or other utility monitoring.

Additional objects, advantages and novel features of the invention willbe set forth in part in the description which follows, and in part willbecome apparent to those skilled in the art upon examination of thefollowing or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and attained by means ofthe instrumentalities and combinations particularly pointed out in theappended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of an illustrative embodiment of anoptical fiber-to-the-home network in accordance with the invention inwhich wavelength division multiplexed information is transmitted to acustomer premises.

FIG. 2 is a four layer stack diagram, useful in explaining the functionsperformed by the elements comprising the fiber optic network shown inFIG. 1.

FIG. 3 is a simplified block diagram of matching fiber optic interfacesused in the network shown in FIG. 1.

FIG. 4 is an illustrative block diagram of a media access controllerused in the network shown in FIG. 1.

FIG. 5 is an illustrative diagram of wavelength routing employed inanother embodiment of the invention.

FIG. 6 is an illustrative diagram of a SONET optical network that may beoptimally used with the dynamic bandwidth access procedure providing aplurality of services to the customer's premises.

FIG. 7 shows the IID 101 of the SONET network embodiment of FIG. 6 inmore detail.

FIGS. 8A, 8B and 8C show exemplary CPE interfaces for residential, smallbusiness and large business customers, respectively.

FIG. 9 shows an alternative embodiment of the invention in whichmultiple wavelengths are delivered to each customer in the network.

FIG. 10 shows a preferred embodiment of CPE transceiver 907 in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An exemplary fiber optics network having dynamic bandwidth allocationaccording to the invention is illustrated in FIG. 1. The IntelligentInterface Device (IID) 101 is one element of the customer premisesequipment (CPE). Although illustrated simply as an optical fiber from atelecommunications central office (CO) to the CPE in FIG. 1, it shouldbe understood that the fiber optic transmission path 104 may be composedof any number of duplex fibers or any plurality of simplex fibers,including a fiber optic bundle. It should also be understood that FIG. 1is a simplified illustration of a network and that the fiber opticnetwork may be of any configuration and may be extremely complicated.

The IID 101 contains a media access controller (MAC) 102, connecteddirectly to fiber optic transmission path 104, which converts inputoptical signals from fiber optic transmission path 104 to electricalsignals and converts electrical signals to optical signals.

A similar media access controller 105 on the network side preferablyconnects to a plurality of fiber optic transmission paths, 104 to104_(N), each one of which is connected to any number of differentcustomer premises, 1 to M. In an embodiment having multiple customerpremises locations, passive optical splitters and couplers (not shown)are preferably used to optically distribute all of the signals on asingle fiber optic transmission path. Each fiber optic transmission path104 to 104_(N), is preferably full duplex with two logical paths.

The serving node, preferably a telephone central office, comprises mediaaccess controller 105 and any number and variety of switched inputsproviding communications and information signals. The network shown inFIG. 1 includes a Switched Multi-megabit Data Services (SMDS) network106, a narrowband telephone switch 107, a broadband switch 108, anoptical switch 109, and a data packet switch 110. The media accesscontroller 105 receives four input rails, each having a differentservice through one of the switches or network connections, andselectively couples each one to a different wavelength transmitted onthe fiber optic transmission paths 104 to 104_(N).

Regardless of the network architecture or other characteristics, thetransmission path over the fiber optic medium 104 is dynamicallymanaged, and the bandwidth is dynamically allocated on a regular basis,by media access controller 105 at the network side and each one of mediaaccess controllers 102 to 102_(M) on the subscriber side. Preferably,the management and allocation of bandwidth is carried via a logicalcontrol link from one of the media access controllers 102 at thecustomer premises back to the CO, and control information is provided tothe media access controllers to dynamically manage the channelizationand assign bandwidth.

INTELLIGENT INTERFACE DEVICE

An important feature of the fiber optics network of the invention is theintelligent interface device (IID) 101, preferably comprising a fullduplex media access controller (MAC) 102 and one or more customerinterfaces, located at the customer premises. The IID 101 is connectedto at least one fiber optic network through MAC 102 and to any number ofdifferent media in the customer premises through appropriate customerinterfaces.

The MAC 102 contains an optical receiver which receives light from fiberoptic transmission path 104 and then converts it directly intocorresponding electrical signals. An optical transmitter convertselectrical input signals to light transmitted directly into fiber optictransmission path 104. MAC 102 and its optical receiver and transmitterare permanent components of the intelligent interface device.

The customer interfaces preferably comprise a number of respectiveservice definition modules, 103 to 103-M, such as those available fromBroadband Technologies (BBT) for use with their FLX fiber-to-the curbsystems. The modules are not permanent. Each of these modules can beindividually loaded into the IID between MAC 102 and the customerinterface, replaced, upgraded by the customer as desired, etc.Description thereof is provided in the Executive Overview of the FLXSystem, Section BBT-200-901, Planning and Engineering, Issue 2.3X,October 1992, pp. 3-28, which is hereby incorporated in its entirety byreference. The service definition may provide conventional services. Forexample, a telephone service definition module would comprise circuitryfor all of the necessary BORSCHT (battery, overvoltage, ringing,supervision, coding, hybrid and test) functionality to provide normaltelephone line service to standard customer premises telephonesconnected to the interface via a twisted wire pair. An ISDN module wouldcomprise the structure and functions of an ISDN PC card, such as theCyberSpace Freedom™ series of ISDN cards available from ISDN*tek.

However, the modules 103 to 103-M in the preferred embodiment of theinvention are not limited to the functions of conventional networkcommunications interfaces. They can support a number of different higherlevel functions and perform other functions such as decoding of theimage compression scheme for full motion video proposed by the MotionPicture Experts Group (MPEG), image processing, etc. For example, adigital video service definition module would perform the functions of aset-top box and, in particular, a digital entertainment terminal (DET).The architecture and functional details of an exemplary DET can be foundin commonly assigned copending U.S. patent application Ser. No.08/380,755 filed on Jan. 31, 1995 and entitled "Digital EntertainmentTerminal with Channel Mapping" or commonly assigned copending U.S.patent application Ser. No. 08/498,265 filed on Jul. 3, 1995 andentitled "Downloading Operating System Software through a BroadcastChannel", both of which are hereby incorporated by reference in theirentirety.

Although the service definition modules 103 to 103-M are preferred, theIID 101 can also include network interface module (NIM) and/orprocessing circuits, such as a MPEG decoder, for receiving broadcast orvideo-on-demand services. The modules also support a variety of othercommunications services, such as telemetry meter reading, energy saving,remote control, etc. The modules support a plurality of differentphysical CPE media such as ISDN, rf coaxial cable, digital coaxialcable, local fiber optics, twisted copper wire pairs. In order tofacilitate routing, the customer interfaces may include, or be connectedto, optical combining networks so that the optical signals can be busedaround the CPE analogous to electrical signals in copper wires.

The IID 101 includes means to receive selection signals from a user viaremote control, direct entry or through the distribution networkinternal to the CPE. The IID responds by transmitting appropriate datasignals over a narrowband signaling wavelength channel on the fiberoptic transmission path 104 to the corresponding MAC 105. The MAC 105 isalso addressable and/or assigned a time slot for signallingcommunications. If the data represents bandwidth request, wavelengthrequest or bit rate request selection signals, the MAC 105 dynamicallyresponds to that data by allocating bandwidth, wavelengths or bit rateconnections as outlined above, and stores data identifying eachsubscriber's selections or preferences for subsequent communications.

The IID 101 can also be provided with a number of interfaces generallydesigned according to the needs of the user. FIGS. 8A, 8B and 8C showthree different optical transceivers. FIG. 8A depicts a transceiver forresidential uses. That transceiver contains a low speed SONET terminalmultiplexer which takes the OC-12 two-way and provides a two-way splitdown to a DS1 internal interface. Standardized service definition modulecards provide an RJ-11 jack for conventional telephone service, an ISDNexternal interface and an ATM data is made available on twisted copperwire pair for interactive video, etc. FIG. 8B illustrates a transceiverdesigned for small business. That transceiver generally is the same asthe residential transceiver in FIG. 8A, except for the addition of ahigh capacity DS-3 output that segregates it in one or more high capservices. The transceiver of FIG. 8C is designed for large business andwould have a high capacity OC-3C optical interface and an SMDSinterface. These interfaces can go into a Private Branch Exchange (PBX).

The logical functions of the IID can best be understood by reference tothe four layer diagram shown in FIG. 2. The layers 1-4 in FIG. 2 are notactual elements or functions. Bottom layer 1 in FIG. 2 represents thephysical layer and is comprised of the medium and the terminatingconnectors for the medium, for example, a twisted copper telephone wirepair and associated RJ-11 jacks. The MAC described above is a level 1device, it converts the optical signals into electrical signals and viceversa.

The next layer, layer 2, is referred to as the data link layer and isthe logic that directly controls the physical layer. The link layer iscomprised of, for example, the input electrical control signals for theoptical transmitter, either digital or analog. This layer performs thewavelength multiplexing and demultiplexing functions of IID 101 byselectively controlling the optical transmitter and receiver of the MAC102.

The next higher layer, network protocol layer 3, accomplishes thesignalling, switching and connection of services to create the network.Although shown as a single layer in FIG. 2, it is the most complicatedof the layers and may be composed of several sub-layers. It includes,for example, communications protocols and discrete switch layers fordisparate services such as Ethernet Local Area Network (LAN), FM,Switched Mega-bit Data Services (SMDS), frame relay, etc. In thenetwork, the corresponding signalling layer also includes Level 1gateways for interactive video and SS7 networks for setting upconnections across virtual switches for narrowband services. In the IID,the layer 3 functionally communicates with such signalling layerelements of the network.

Layer 4 rides on top of all of these other layers and constitutes theactual data being communicated from one party to another on the network.The payload, such as a video signal, can exist and remains the same indifferent network set-ups corresponding to layer 3 (ATM or SONET),different physical links comprising layer 2 (wavelength divisionmultiplexing or time division multiplexing), and different physicalmedium in layer 1 (either fiber optic, electrical wire, wirelesstransmission, etc.).

Layers 1-4 represent different levels of complexity in which there canbe alternative implementations. For example, video can be transportedover either coaxial cable or fiber optics (different physical layer).The signals can be wavelength division multiplexed or time divisionmultiplexed on the physical medium. The multiplexing can occur in an ATMnetwork or a SONET network.

Most of the expense incurred in the installation of large bandwidthfiber optic networks is associated with the physical equipment (fiberoptics, optical splitters, O/E converters, etc.) in physical layer 1.Cost effective advantages can be achieved by effectively using thebandwidth through optimum development of the equipment, protocols andprogrammed logic corresponding to layers 2 and 3, in particular, theswitching of different bandwidth services and services operatingdifferently at the upper level, network level 3. Current fiber opticsystems typically handle level 3 operations by a number of discreteswitches, each corresponding to a respective service such as EthernetLAN, FM, SMDS, frame relay, etc., which are located exclusively in thecentral office. Such level 3 operations are handled or controlled, atleast in part, by switches and other equipment within the intelligentinterface device of the preferred embodiments.

Media access controller 102 of IID 101 shown in the preferred embodimentof FIG. 1 contains an interface between physical layer 1 and the higherlayers and carries out level 1 functions. It channels optical andelectrical signals of varying bit rates and formats to and from thephysical medium.

The downstream optical signals can be broken down into individualelectrical bits, frames or packets, which are output to be decoded inlevel 3 by the service definition modules 103 to 103-M of the IID 101,and then delivered to the electrical devices in the CPE and converted tophysical layer 4 output. For example, the optical signals can representMPEG encoded video, then can be converted to electrical signals anddecoded by an MPEG decompression circuit and D/A converted into abaseband video signal in a service definition module and then deliveredto a television set and converted to a displayed image.

In the preferred embodiment shown in FIG. 1, fiber optic transmissionpath 104 is preferably a single multi-fiber optical pipe, and mediaaccess controllers 102 and 105 carry out wavelength divisionmultiplexing and time division multiplexing of the signals transportedon the pipe. Spatial division is also carried out by passively splittingthe different fibers of the pipe and terminating them at differentcustomer premises.

The wavelength division multiplexing is carried out to the maximumextent safely permitted by the physical properties of the fiber optics.Presently available equipment is capable of effectively operating inthree separate wavelength regions: 850 nm, 1300 nm, and 1550 nm. Eachwavelength region can support many separate discrete wavelengths. Forexample, in the 1300 nm region, there is a 1290 nm wavelength signal, a1300 nm wavelength signal and a 1310 nm wavelength signal. Theincrements of permissible wavelength divisions and the amount of loss ordispersion vary in the different wavelength regions. For example, the1550 nm region has the lowest loss, but the 1300 nm region has the bestdispersion characteristics.

Of course, there may be more than the three specific wavelength regionsmentioned above, and each wavelength region may have wavelengthdivisions controlled down to the 10ths or hundreds or thousands ofAngstroms. In such a case, a larger number of wavelength multiplexedsignals are available for simultaneous use.

FIG. 4 shows a preferred embodiment of media access controller 105. Aseparate laser is used for each wavelength. The lasers can each be onseparate semiconductor chips, but the optical transmitter in thepreferred embodiment is comprised of a single integrated (IC) chip 401.The IC 401 has an array of 4, 8 or 16 lasers, each one of which producespulses at a different wavelength within a common wavelength region. Thelasers are not variable or tunable, but the transmitting wavelength(s)are selectable.

The physical light pulses produced by the lasers on IC 401 are actuallycoupled by integrated optics and supplied directly into a single fiber402 so that the light is already wave division multiplexed when it isinput into the fiber. The bandwidth of the combined output of the fourlasers is in the 10-50 Gb/s range using presently available commercialequipment. If even more bandwidth or multiplexing is necessary, twolaser array ICs may be used with an optical combiner/coupler to feed theoutput of both into one optical fiber.

All of the lasers operating in a single wavelength region are preferablymade from a common substrate (for example, indium phosphate for lasersin the 1300 nm wavelength region) so that the relative difference inwavelength between the lasers is very stable. For example, if there isan increase in temperature of an IC which causes the wavelength of a1300 nm laser to increase to 1304 nm, the output of a 1310 nm wavelengthlaser on the same chip will similarly increase to approximately 1314 nm.Therefore, the difference between the output wavelengths will stayapproximately constant at 10 nm and will not decrease to 6 nm. Thewavelengths consequently always have guardbands to preventintermodulation.

The semiconductor lasers operating at discrete wavelengths withindifferent wavelength regions are fabricated on different semiconductorchips, each chip corresponding to one of the wavelength regions. Theoutputs of each chip are then combined in an optical combiner/coupleronto the fiber. However, if fabrication technologies develop to thepoint where lasers operating at wavelengths of different wavelengthregions can be placed on the same substrate, then a single chip can beused.

The optical receiver 403 has to be able to selectively receive anddetect each one of the wavelengths on fiber optic 104. Receiver 403could be controlled so that the light from optical fiber 104 goes to adetector that is only sensitive to the desired wavelength. However, itis preferable for optical receiver 403 to receive all of the differentwavelengths on the fiber 104. A wavelength dependent splitter 404selectably and optically splits the wavelengths and sends eachwavelength to a separate detector 406₁ to 406₄. Each one of the separatedetectors is generally comprised of the same broadband detector, such asan avalanche diode, which has a relatively flat sensitivity response forall of the wavelengths on fiber 104.

The illustration of the laser array constituting the optical transmitterand the wavelength dependent splitter of the optical receiver in FIG. 4is essentially functional. Similarly, I/O and media access logic section407 is illustrated as merely performing the function of obtaining andforwarding the appropriate inputs to the optical transmitter andaccepting the outputs of the optical receiver. However, I/O and mediaaccess logic section provides switchability and performs the level 2 and3 functions described elsewhere in this application.

An important feature of the invention is that the central office mediaaccess controller 105 can best be thought of as having a matchinginterface with each one of a plurality of media access controllers 102in corresponding customer premises. FIG. 3 illustrates a pair of suchmatching optical interfaces 301, preferably SONET interfaces, connectedvia optical fiber 104. The optical interfaces are preferably identicalto each other, the only difference being between the I/O and mediaaccess logic section of the central office media access controller 105and the CPE media access controller 102.

The IID 101 interacts with the central office in a dynamic media accesscontrol procedure to decide the allocation of wavelengths and bandwidthsto customers for each call or service at required bit rates. Inparticular, the dynamic bandwidth assignment can be carried outintra-session at the customer's request. For example, when a customer onhis or her computer connected to an information service through thenetwork desires to transmit or receive a large amount of large bandwidthdata such as video, he can request that the bandwidth to his premises besubstantially increased. If the customer has an optical customerinterface on his or her IID and an optical card in the computer, thebandwidth can be increased up to the bandwidth of the fiber coming intothe premises.

The following execution of a narrowband telephone call is given as anexample of the dynamic bandwidth allocation procedure in the embodimentof FIG. 1. When a telephone set 111 goes off-hook a relay closes andcurrent flows through the telephone and twisted wire pair 112. Theintelligent interface device 101 recognizes this as an off-hookcondition. In response, the interface 101 transmits a request for dialtone upstream over fiber 104, via some established signaling channel andpredefined signaling protocol. If the bandwidth necessary for thetelephone call is available on fiber 104, the interface at the centraloffice or corresponding MAC 105 allocates a wavelength and a time sloton fiber 104 to the desired telephone call and transmits back asignaling message identifying the allocated wavelength and time slot tothe interface device 101 at the customer premises. The interface at thecentral office concurrently establishes a connection to narrowbandtelephone switch 107. At this point, the fiber optic system hasestablished a telephone grade link through from the telephone set 111 tothe narrowband telephone switch 107, and the switch 107 can acceptdialed digits and complete the call through the PSTN in the normalmanner. Similar procedures are used to obtain broadband channels andassociated signaling channels on fiber 104 and establish connections toappropriate broadband switching systems, such as broadband switch 108,to set up sessions with video information providers, e.g. for video ondemand type services.

When bandwidth allocation is employed using wavelength divisionmultiplexing (WDM), a large bandwidth, completely fiber optic systembecomes much more economically feasible. The physical interfacesnecessary for fiber optic transmission of 2 gigabits per second (2 Gb/s)over a single wavelength (optical transmitter, fiber optic and opticalreceiver) are very expensive. It is cheaper to use, for example, foursets of 500 Mb/s interface equipment for four separate wavelengths onthe fiber.

In addition to transmitting and receiving light in different wavelengthbands as described above, the media access controllers 102 and 105 alsocontrollably perform the modulation and demodulation of the light on aselectable basis. They carry out coherent transmission and subcarriermodulation of light on the fiber, with ample consideration given inorder to prevent beats from occuring between wavelengths. The use of Nwavelengths in an optical fiber generally multiplies the bandwidth ofthe fiber by a factor of N. The number N which is practically obtainableis restricted by the physical properties of either the transmitter, thefiber optic or the receiver. The number may increase with improvementsin one or all of these elements, but the distinguishing characteristicsof this invention will remain for all values of N.

Because of the cost associated with the physical transceivers necessaryto convert the optical signals of very high bandwidths to electricalsignals and vice versa, wavelength division multiplexing creates acheaper transmission path for distribution than time divisionmultiplexing in fiber optic networks. The large savings achieved at thephysical layer, layer 1 in FIG. 2, more than compensates for thecomplexity introduced into layers 2 and 3. The different wavelengths maybe used for different services or for different customer premises.Separation of wavelengths for each customer provides security in thedistribution of information because one customer premises does notreceive the information selectively distributed to another customerpremises.

A preferred embodiment for distribution (separation and routing) of thewavelength multiplexed signals is illustrated in FIG. 5. The opticaltransmitter 401 of MAC 105 is connected to the optical receiver in eachone of a plurality of customer premises and transmits and receives, fullduplex, a multiple number (n) of different wavelengths. A passivewavelength dependent splitter 501 receives the fiber optic signals fromthe optical transmitter 401 and separates the transmitted opticalsignals by wavelength into two legs, thereby demultiplexing thewavelength division multiplexed optical signals according to wavelength.Each leg is input to another wavelength dependent splitter 502 whichsplits the leg into two wavelengths.

Each one of the separated wavelengths is forwarded to a correspondingCPE wherein it is received by one of the MAC's 102₁ to 102₄. Thestructure of the physical interface of MAC 102 does not need to bedifferent than the physical interface of the central office MAC 105. Theoptical receiver is controlled to be responsive to the separatedwavelength and the laser in the transmitter array which corresponds tothe separated wavelength is selected and controlled for transmittingoptical signals to MAC 105. Multiplexing and demultiplexing no longermust be carried out by IID 101. Dynamic media access control occursthrough control of the allocation of wavelengths to each one of theplurality of customer premises and/or to each one of a plurality ofdifferent requested services further up in the network.

SONET NETWORK

A synchronous optical network (SONET), connected to the CPE according tothe present invention and utilizing the intelligent interface device ofFIG. 4, is shown in FIG. 6.

The basic module or first level of the Synchronous Optical Network(SONET) signal is called the Synchronous Transport Signal-Level 1(STS-1). The STS-1 has a bit rate of 51.84 Mb/sec and is synchronous.The STS-1 signal is formed from a sequence of repeating frames. TheSTS-1 frame is illustrated in FIG. 2 of U.S. Pat. No. 5,293,376. TheSTS-1 frame structure can be drawn as 90 columns by 9 rows of 8-bitbytes. The order of transmission of the bytes is row by row, from leftto right across the columns, with one entire frame being transmittedevery 125 micro-seconds. The 125 micro-second frame period supportsdigital voice signal transport encoded using 1 byte/125 micro-seconds=64kb/s. The first three columns of the STS-1 frame contain section andline overhead bytes. The remaining 87 columns form the STS-1 SynchronousPayload Envelope (SPE). The SPE carries SONET payloads including 9 bytesof path overhead. The STS-1 can carry a clear channel DS3 signal (44.736Mb/s) or, alternatively, a plurality of lower-rate signals such as DSO,DS1, DSlC, and DS2 by dividing the Synchronous Payload Envelope into aplurality of fixed time slots. For example, 648 DSO signals fit into theSPE of an STS-1 signal.

Higher rate SONET signals are obtained by byte interleaving N framealigned STS-1 signals to form an STS-N signal in accordance withconventional SONET technology. An STS-N signal may be viewed as having arepetitive frame structure, wherein each frame comprises the overheadbits of N STS-1 frames and N synchronous payload envelopes. For example,three STS-1 signals may be multiplexed by a multiplexer into an STS-3signal. The bit rate of the STS-3 signal is three times the bit rate ofan STS-1 signal and the structure of each frame of the STS-3 signalcomprises three synchronous payload envelopes and three fields ofoverhead bits from the three original STS-1 signals. When transmittedusing optical fibers, the STS-N signal is converted to optical form andis designated as the OC-N signal. A more detailed description of SONETappears in U.S. Pat. No. 5,293,376 and in Davidson et al, The Guide toSONET, Telecom Library Inc., 1991, both of which are hereby incorporatedby reference in their entirety.

The SONET network of FIG. 6 preferably comprises a plurality of fiberoptic hubs 601₁, 601₂, to 601_(N) on the SONET network side of the fiberoptic medium of ring 602. Each fiber optic hub can drop and add opticalsignals to and from the SONET ring 602. The SONET ring 602 may receivesignals from a variety of input sources and distributes those signalsthrough the media access controllers 105₁ to 105_(N). Each one of therespective media access controllers 105₁ to 105_(N) contains the sameoptical transmitter 401 and optical receiver 403 shown in FIG. 4.However, the I/O and media access control logic sections are differentand provide a switchable connection to SONET gateway mux 603 throughSONET ring 602 instead of to the switches shown in FIG. 1. The SONETgateway multiplexer 603 has a plurality of network interface cards 604for receiving a variety of inputs. For example, a narrowband switch 605provides narrowband telephone communications from telephone network 606.An ATM switch 607, connected to SONET gateway multiplexer 603, couplesATM signals to and from ATM switch 607 on the SONET ring 602. The linksto SONET gateway mux 603 and the ATM switch 607 may be those incopending, commonly assigned, patent application Ser. No. 08/413,215filed on Mar. 28, 1995 entitled "Full Service Network with DistributedArchitecture", which is hereby incorporated by reference in itsentirety.

These inputs to the gateway 603 preferably include narrowband transportfor voice and narrowband data services. A digital switch or an analogimplementation of a Service Switching Point (SSP) switch 605 providesstandard type plain old telephone service (POTS) for telephone customers606. The digital POTS switch provides a DS1 type digital input/outputport through interfaces conforming to either TR008 or TR303. The DS1goes directly to a SONET gateway multiplexer 603. The multiplexer mayalso receive telephone signals in DS1 format from an analog switchthrough a central office terminal. The central office terminal convertsanalog signals to digital and digital signals to analog as necessary toallow communication between the analog switch and the rest of thenetwork.

The signals are made available at one of the SONET drop/add hubs 601 andwavelength multiplexed by the corresponding MAC 105 (possibly timedivision multiplexed with a number of DS1 signals) for transmission overone wavelength on the fiber optic transmission path 104 to IID's 101.

A preferred embodiment of the IID 101 for use in the SONET network ofFIG. 6 is shown in FIG. 7. Each IID 101 preferably contains an opticalinterface 701 for two-way conversion between optical and electricalsignals, a SONET terminal multiplexer 702, and a plurality of servicedefinition module cards 703₁ to ⁷⁰³ _(M). Preferably, one of the servicedefinition modules 703 provides telephony service through SONET terminalmux 702 in compliance with TA-TSY-000303, IDLC System GenericRequirements, Objectives and Interface: Feature Set C--SONET interface(Supplement 2); Bellcore, Issue 3, December 1987, hereby incorporated byreference. The standard protocol for MUX 702 to signal with SONETdrop/add fiber hubs 601₁ to 601_(N), and the functionality of MUX 702are defined in TA-TSY-000253, SONET Transport Systems: Common GenericCriteria; Bellcore, Issue 5, February 1990. Other services are alsoprovided by other service definition modules 703 through SONET terminalmux 702. One of the service definition module cards preferably providesATM cells as output with STS-1 interface on twisted pair to an ATMPacket Assembler/Disassembler (PAD) 704 and a terminal device 705.

The ATM switch 607 receives and outputs broadcast video signals 609and/or video signals from a Level 2 Gateway 610 under the control ofLevel 1 Gateway 608. The ATM switch 607 uses known encoding technologyto provide various network identifiers (e.g., VPI/VCI values) that takethe service signals through the fiber optic network to correspondingbroadband electrical devices at the customer premises. The networkidentifiers are preferably used only in ATM service signals at differentnetwork nodes in a manner consistent with that in copending, commonlyassigned, patent application Ser. No. 08/413,215 filed on Mar. 28, 1995entitled "Full Service Network with Distributed Architecture", herebyincorporated by reference in its entirety. The Intelligent InterfaceDevices 101 which optically receive those service signals, convert themto electrical signals and deliver them to electrical devices in thecustomer premises based in part on the network identifiers.

Of course, the broadband SONET network shown in FIG. 6 may have anynumber of connected sources and end users and may deliver any type of,or any number of types of, broadband information. For example, thenetwork could also transmit digital multimedia information and thecustomer premises equipment could include a personal computer andcomputer monitor instead of, or in addition to, a DET and television.The broadband information is made available at one of the SONET drop/addhubs 601 and wavelength multiplexed by the corresponding MAC 105(possibly time division multiplexed with a number of DS1 signals) fortransmission over one wavelength fiber optic transmission path 104.

The network executes the dynamic media access control in three phases.As an illustrative example, consider a telephone call. A twisted pairconnection is established through the customer premises to the interfacedevice when a telephone goes off-hook. A channel is developed on awavelength for the signaling communications of the dynamic media accesscontrol procedure carried out between each IID 101 and a correspondingMAC 105 using either an asynchronous optical protocol, or thesynchronous (SONET) OC rate transport. The signaling information may bebroadcast over all of the fiber optic couplings, 612₁ to 612_(N) tooptical coupler 611 in a time division multiplexed channel. In thiscase, each one of the IID's 101 is addressable and/or is assigned apredetermined time slot and includes means to selectively receive anddecode the signalling data indicating the bandwidth allocation for thatIID 101. Using the signalling channel, the MAC 102 in the interface 101then negotiates with MAC 105 to obtain a bandwidth path for the voice onan assigned wavelength on fiber path 104. The MAC 102 performsmultiplexing and demultiplexing in accordance with the decoded dataobtained and stored by the IID 101, to provide two-way communication viathe allocated bandwidth.

The fiber optic network of FIG. 9 comprises a serving node transceiver901, a bi-directional wavelength division multiplexed optical fiber 902and a 1 to 2 passive power splitter/combiner 903. Transceiver 901receives all of the various available services (video, telephony data,POTS, etc.) as inputs 909₁ to 909_(N) controllably interconnected to anumber of lasers (not shown), each operating at a wavelength availablein fiber optic 902.

In the downstream direction from serving node transceiver 901 to eachone of the CPE's 907, passive power splitter/combiner 903 splits lightfrom optical fiber 902 and couples the light into two fibers 904. Eachfiber 904 has all of the wavelengths on it and is, in turn, coupled toone of the passive power splitter/combiners 905, which again splits thelight into four equal parts for transmission over four identical fibers906 with all wavelengths on each fiber. Each one of the fibers 906provides a downstream light input to a respective one of the four CPE's907.

In the upstream direction from CPE's 907 to serving node transceiver901, passive power splitter/combiners 905 combine light from four fibers906 into light for transmission over a single fiber 904. The passivepower splitter/combiner 903 combines the light from two fibers 904 intolight for transmission over one fiber 902 to the transceiver 901.

All of the fibers 902, 904 and 906 in the embodiment shown in FIG. 9 arebidirectional. The passive power splitter/combiners are preferablypurely passive, carry all wavelengths to all customers and to alltransceivers and combine all return wavelengths from all of thecustomers and the transceivers. The elements form a shared busarchitecture with a fiber bus wherein the fiber optic links carry allfrequencies over fixed distances.

An alternative embodiment of the network can employ two separateuni-directional transmission paths: one in the direction from servingnode transceiver 901 to CPE's 907 and the other in the direction fromCPE's 907 to serving node transceiver 901. Each transmission path uses arespective set of fibers carrying traffic in only one direction and useseither splitters or combiners instead of integrated splitter/combiners.Although such an embodiment will generally be more expensive than anembodiment with bi-directional fibers, it is not critical that thesplitters and combiners be passive.

Another alternative embodiment of the network can serve a larger numberof CPE's 907, such as nine or sixteen, simply by using a differentnumber of 1 to 2 passive power splitter/combiners or by using 1 to 3passive power splitter/combiners or 1 to 4 passive powersplitter/combiners instead of the 1 to 2 passive powersplitter/combiners.

There are similarities and differences between the embodiment shown inFIG. 9 and an embodiment in which wavelengths are discriminated in thenetwork and only one single wavelength or wavelength region is deliveredto each CPE (e.g., FIG. 5 in which one wavelength or wavelength regionis provided to each premise and carries all of the information for thatpremise and all other wavelengths in the network are blocked) . Thetransceiver 901 at the serving node in the embodiment of FIG. 9 is verysimilar to the transceiver of media access controller 105 in theembodiment of FIG. 1, the only slight difference being in the logic ofthe control program or software so that the network is managed a littledifferently.

The discrimination of wavelengths by the CPE 907 is crucial to theembodiment of FIG. 9 and an important difference lies in the controllingmanagement of multiple wavelengths by the I/O and media access controllogic section in CPE transceiver 908. The relationship between theoptical transceiver and the media access control logic section isdiscussed above with respect to FIG. 4. Each transceiver 908 in the CPE907 of FIG. 9 is able to access all wavelengths. When a particularsubscriber or particular subscriber device needs bandwidth and/or acommunication link, media access controller 911 performs a managementfunction that allocates and controls the bandwidth and/or communicationlink to the transceiver 908. The media access controller 911 alsocontrols the input and output of electrical signals to the opticaltransceiver 908 in order for them to be transmitted and received overthe bandwidth and/or communication link that it has allocated andcontrolled. The management function preferably also specifies thewavelength which is going to be used and, if it istime-division-multiplexed, the timeslots of that wavelength that aregoing to be used as well. The optical transceiver 908 performs only thefunctions of O/E conversion, E/0 conversion, transmission of opticalsignals and reception of optical signals.

Preferably, the transceiver 908 has a tunable laser for transmissionback to the network as well as a tunable detector of some sort for thedetection of optical signals on the specified wavelength or multiplewavelengths as shown previously in FIG. 4. The tunable laser ispreferably a selectable laser array in which each one of a plurality oflasers operates at a predetermined wavelength.

In one embodiment, all of the downstream traffic to a CPE 907 isallocated on only a single wavelength and transceiver 908 of that CPE"tunes into" that wavelength in order to derive all of the POTS, ISDN,ATM, video, etc., traffic off of that one wavelength. The singlewavelength is not shared with other CPE's while in use. The downstreamwavelength appears at different homes, but it is not assigned todifferent homes at the same time. The one wavelength is used up to itscapacity. If the CPE's traffic demands went beyond the capacity of thesingle wavelength, then the serving node of the network allocates thecustomer a second wavelength which is used in the same way as the singlewavelength. The upstream traffic is preferably allocated to the samewavelength as the downstream traffic, but it can also be allocated to adifferent wavelength. The upstream traffic is inherently received onlyat the serving node transceiver and cannot be received by differenthomes. (In an alternative embodiment, the video traffic can be onewavelength, POTS on another wavelength, etc.)

A subscriber gets basic low bandwidth services, and the CPE transceiver908 makes calls through network connections and carries out two-waycommunications all the way to network transceiver 901 according to thefollowing description made with reference to FIG. 10. The functionalityof transceiver 908 is expanded to have POTS delivered into the house ontwisted wire pair. The preferred embodiment shown in FIG. 10 includes anISDN terminal adapter 1001 that provides conventional ISDN on thecentral office side and looks like a POTS line on the customer side.ISDN terminal adapter 1001 converts from POTS signaling to ISDNQ.921/Q.931 signalling, performs analog-to-digital and digital-to-analogconversion and has a plurality of different call control message setsinstalled. The central office switches (not shown) also have the ISDNprotocols installed.

When a phone at CPE 907 goes off-hook, the terminal adapter exchangesmessages with the switch using the D-channel of the ISDN to more or lessget the switch's attention. A Link Access Procedure-D (LAP-D) protocolallows a link to serve multiple users. The switch then establishes callset-up, sends a message instructing the terminal adapter 1001 to providedial tone on twisted wire pair and sets up a DS-1 path.

Preferably, the terminal adapter provides a primary rate interface (PRI)ISDN (23B+D) on a DS-1 channel on the network side. The D channel isused for signalling the call control. A SONET multiplexer 1002time-division-multiplexes (TDM) the DS-1 up to a higher rate and alsoprovides DS-3 and OC-3 interfaces to provide high bit rate data servicessuch as video services. All of the different types of traffic, includingthe PRI ISDN signal, are time-division-multiplexed by TDM SONET MUX1002; and the multiplexed signal is used to modulate a laser whichoutputs signals on a single respective wavelength λ₁ to the network.

Each TDM SONET MUX 1002 is preferably assigned a different wavelengthfor signalling to avoid collisions at optical combiners. However, acommon default wavelength may be used by each of the receivers as acommon signaling channel with a random access technique such as slottedALOHA in which each transceiver 908 is active during a certain timeinterval.

A small amount of certain traffic, such as OC-1 carrying the POTS orISDN service, may be permanently assigned to the primary wavelength λ₁in a static mode so as to provide continuous services. All services toand from the CPE can be handled up to the OC-1 rate before any bandwidthadjustments are made. The idle channel traffic is going to the Dchannel. The only traffic going to the network in an idle condition isthe idle signalling channel information in wavelength λ₁.

Additional narrowband services and all broadband services aredynamically allocated bandwidth through control of TDM SONET MUX 1002.Bandwidth is dynamically allocated through the manipulation ofwavelengths within the fibers and time-division-multiplexing withinwavelengths. The dynamic allocation includes a negotiation between a CPEmedia access controller (CPE MAC) 911 providing program control oftransceiver 908 in CPE 907 and a serving node media access controller(MAC) 910 providing program control of serving node tranceiver 901.Although shown in FIG. 9 as being connected by a separate token bus 912,CPE MAC 911 and MAC 910 communicate over wavelength λ₁₊₁ in the fiberoptic network. Serving node transceiver 901 has ultimate control overdelegating the bandwidth and CPE transceiver 908 is more or less themaster allotting bandwidth for corresponding CPE 907.

As mentioned above, all wavelengths λ₁ to λ_(N) carry data and aredelivered to each one of CPE transceivers 908. The additional wavelengthλ_(N+1) is preferably used as a common signalling wavelength whichcarries all the media access bids for control. Each CPE transceiver 908has a tunable optical transmitter and a tunable discrete receiver whichare capable of discriminating all of the various wavelengths includingthe media access wavelength.

When a terminal device in the CPE 907 requests or needs wavelength(s) inaddition to the statically allocated wavelength to carry out a service,the transceiver 908 determines which one of the wavelengths is idlethrough negotiations transmitted over the media access wavelength andassigns the idle wavelength(s) to transceiver 908.

The negotiations over the media access wavelength can be made inaccordance with any one of a number of protocols used to avoidcollisions, such as LAP-D or slotted aloha. A preferred embodiment ofthe invention uses a token bus operating in the 1 megahertz or higherrange so that it seems almost instantaneous to each customer. Thenetwork signalling system in control of assigning the idle wavelengthsis also the token controller and it passes out the token to each one ofthe terminal devices. The token is the limiter for coverage of the mediaaccess controller module set. It gives each terminal device, atdifferent times, the option to send a signalling message using a token.

Although shown in the figures and frequently referred to as a house orother location, it is to be understood throughout this application thatthe customer premises may constitute any type of premises such as aschool, an office, an apartment building, an office building, etc. TheCPE may also be comprised of a plurality of premises, separated by asmall distance such as a housing subdivision, a university campus, etc.The CO may be a telephone company central office containing otherequipment and providing other services. Although shown and referred toas a central office, the CO may comprise any serving node which isgeographically distant from the CPE.

While the foregoing has described what are considered to be preferredembodiments of the invention, it is understood that variousmodifications may be made therein and that the invention may beimplemented in various forms and embodiments, and that it may be appliedin numerous applications, only some of which have been described herein.It is intended by the following claims to claim all such modificationsand variations which fall within the true scope of the invention.

We claim:
 1. A fiber optic communications network comprising:a servingnode telecommunications transceiver transmitting a first plurality ofoptical communications and information signals; a plurality of customerpremises equipment systems, each one of said customer premises equipmentsystems comprising:a customer optical transceiver for receiving saidfirst plurality of optical communications and information signalstransmitted by said serving node telecommunications transceiver, fortransmitting a second plurality of optical communications andinformation signals to said serving node telecommunications transceiver,and for performing wavelength division multiplexing and demultiplexingof said first and second plurality of optical communications andinformation signals, and a terminal device providing communicationservices requiring different bandwidth allocations or a plurality ofterminal devices requiring different respective bandwidth allocations; afiber optic transmission path connecting said serving nodetelecommunications transceiver to said customer optical transceiver ineach one of said plurality of customer premises equipment systems, saidserving node telecommunications transceiver controllably transmittingsaid first plurality of optical communications and information signalsto each optical transceiver at a plurality of wavelengths over saidfiber optic transmission path and controllably receiving said secondplurality of optical communication and information signals from eachcustomer optical transceiver over said fiber optic transmission path; aplurality of optical elements, said optical elements splitting the firstplurality of optical communication and information signals transmittedby said serving node telecommunications transceiver into a plurality ofsplit optical signals, said split optical signals containing all of thewavelengths of said first plurality of optical communication andinformation signals transmitted by said serving node telecommunicationstransceiver, and forwarding each one of said split optical signals to arespective one of said customer premises, and said plurality of opticalelements combining said second plurality of optical communication andinformation signals received from said customer premises into a combinedoptical signal and forwarding said combined optical signal to saidserving node telecommunications transceiver; and a media accesscontroller connected to and controlling said customer opticaltransceiver, so as to dynamically provide said different bandwidthallocations over said fiber optic transmission path connecting saidserving node telecommunications transceiver to said plurality ofcustomer premises by assigning one or more of said plurality ofwavelengths to said customer optical transceiver.
 2. A fiber opticcommunications network according to claim 1, wherein said plurality ofoptical elements comprises a plurality of passive power opticalelements.
 3. A fiber optics communications network as recited in claim1, wherein said fiber optic transmission path comprises at least onefull duplex optical fiber.
 4. A fiber optic communications networkaccording to claim 3, wherein said plurality of optical elementscomprises a plurality of passive power integrated splitter/combiners. 5.A fiber optics communications network as recited in claim 1, whereinsaid fiber optic transmission path comprises simplex optical fibers. 6.A fiber optic communications network according to claim 5, wherein saidplurality of optical elements comprises a plurality of passive powersplitters and a plurality of passive power combiners.
 7. A fiber opticscommunications network as recited in claim 1, wherein said serving nodetelecommunications transceiver comprises a narrowband switch providingvoice grade telephone service routing and a broadband switch providingrouting for broadband services.
 8. A fiber optics communications networkas recited in claim 7, wherein said serving node telecommunicationstransceiver further comprises an asynchronous transfer mode switch.
 9. Afiber optics communications network as recited in claim 8, wherein saidserving node telecommunications transceiver transmits optical servicesignals, containing network identifiers different from said first orsecond plurality of optical communications and information signals, oversaid fiber optic transmission path; andwherein each of said customeroptical transceivers receive said optical service signals, converts saidoptical service signals into electrical signals and selectively deliversthe electrical signals to electrical devices in the customer premises inaccordance with said network identifiers.
 10. A fiber opticscommunications network as recited in claim 7, wherein:narrowbandcommunications for said customer premises is permanently allocated toone of said plurality of wavelengths; and said media access controllerdynamically provides said different bandwidth allocations for saidbroadband services.
 11. A fiber optics communications network as recitedin claim 7, wherein said serving node telecommunications transceiverfurther comprises an optical switch providing optical signals from anoptical network.
 12. A fiber optics communications network as recited inclaim 1, wherein said first plurality of optical communications andinformation signals from said telecommunications central office aretransmitted simultaneously on said plurality of wavelengths and each oneof said customer optical transceivers contains an optical receiverreceiving all of said plurality of wavelengths and controllablydiscriminating said plurality of wavelengths.
 13. A fiber opticscommunications network as recited in claim 12, wherein said customeroptical transceiver comprises at least one service definition module.14. A fiber optics communication network as recited in claim 13, whereinsaid at least one service definition module is responsive to signallingcommunications received over said optical fiber for controlling saidwavelength dependent multiplexer and demultiplexer in accordance withsaid signalling communications.
 15. A fiber optics communicationsnetwork as recited in claim 1, wherein said first plurality of opticalcommunications and information signals from said serving nodetelecommunications transceiver are transmitted simultaneously on atleast three different wavelengths and each one of said customer opticaltransceivers performs format conversions of said first plurality ofoptical communications and information signals from said serving nodetelecommunications transceiver.
 16. A fiber optics communicationsnetwork as recited in claim 1, wherein the media access controllerperforms a dynamic media access control procedure.
 17. A fiber opticscommunications network as recited in claim 16, wherein said dynamicmedia access control procedure supplies individual services anddynamically provides said different bandwidth allocations upon demand bya customer.
 18. A fiber optics communications network as recited inclaim 8, wherein said different bandwidth allocations include thedynamic allocation of said plurality of wavelengths.
 19. A fiber opticscommunications network as recited in claim 18, wherein said dynamicallocation of said plurality of wavelengths is performed in response toa demand by said customer.
 20. A fiber optics communications network asrecited in claim 18, wherein said dynamic media access control procedureincludes the dynamic allocation of bit rates of said first or saidsecond plurality of optical signals in response to a demand by saidcustomer.
 21. A fiber optics communications network as recited in claim1, wherein at least one of said customer optical transceivers comprisesa SONET multiplexer.
 22. A fiber optics communications network asrecited in claim 16, wherein said media access controller is addressableby said telecommunications central office.
 23. A fiber opticscommunications network as recited in claim 16, wherein said media accesscontroller performs said dynamic media access control procedure bycausing said customer optical transceiver to transmit a bandwidthrequest signal at a common channel signalling wavelength over said fiberoptic transmission path, said common channel signalling wavelength beingseparate from said plurality of wavelengths carrying said first orsecond plurality of optical communication and information signals.
 24. Afiber optics communications network as recited in claim 23, wherein saidmedia access controller communicates with said serving nodetelecommunications transceiver to determine which one of said pluralityof wavelengths carrying said first or second optical communications andinformation signals are idle and allocating said idle wavelengths.
 25. Afiber optics communications network as recited in claim 23, wherein saidbandwidth request signal is transmitted in response to user inputs. 26.A fiber optics communications network as recited in claim 25, whereinsaid user inputs are received from a remote control.
 27. In a fiberoptic communications network including a serving node telecommunicationstransceiver, a plurality of customer premises equipment systems, eachsystem including a customer optical transceiver, a media accesscontroller, and at least one terminal device requiring differentrespective bandwidth allocations, and a fiber optic transmission pathincluding a plurality of optical elements, for connecting the servingnode telecommunications transceiver to each customer opticaltransceiver, a method comprising the steps of:transmitting a firstplurality of optical communication and information signals at aplurality of wavelengths from the serving node telecommunicationstransceiver; splitting the first plurality of optical communication andinformation signals into a split plurality of optical signals, the splitoptical signals containing all of the wavelengths of the first pluralityof optical communication and information signals; controllably receivingsaid first plurality of optical communications and information signalsat each customer optical transceiver; performing wavelength divisiondemultiplexing of said first plurality of optical communications andinformation signals; performing wavelength division multiplexing of asecond plurality of optical communications and information signals;transmitting the second plurality of optical communications andinformation signals from at least one customer optical transceiver tothe serving node telecommunications transceiver; combining thetransmitted second plurality of optical communication and informationsignals into a combined optical signal and forwarding the combinedsignal to the serving node telecommunications transceiver; anddynamically controlling the customer optical transceiver to providedifferent bandwidth allocations over the fiber optic transmission pathto the at least one customer optical transceiver.
 28. The method ofclaim 27, wherein the step of dynamically controlling includes the stepof dynamically providing the different bandwidth allocations upon demandby customer.
 29. The method of claim 27, wherein the step of dynamicallycontrolling includes the step of dynamically allocating the plurality ofwavelengths.
 30. The method of claim 27, wherein the step of dynamicallycontrolling includes the step of dynamically allocating bit rates of thefirst or the second plurality of optical signals in response to a demandby a customer.
 31. The method of claim 27, wherein the step ofdynamically controlling includes the steps of:causing said customeroptical transceiver to transmit a bandwidth request signal at a commonsignalling wavelength over the fiber optic transmission path;determining which one of the plurality of wavelengths carrying the firstor second optical communications and information signals is idle; andallocating said idle wavelength.